Various systems include components, such as valves, that may be automatically moved to one or more positions, under the control of one or more other system components, during system operation. These components may be moved periodically or in response to certain conditions that may occur within the system. In either case, it is preferable to know that the component being moved has actually been, or is being, moved from its initial position to its desired position. It is also preferable to know that the component remains in the desired position once it has been moved. Thus, numerous systems and methods have been developed to sense, and supply signals representative of, the position of various moveable components.
Some examples of position sensors that have been developed include potentiometers, rotary variable differential transformers (RVDTs), linear variable differential transformers (LVDTs), capacitance position sensors, and Hall effect sensors, just to name a few. Although these, and other, known types of position sensors are generally reliable, each suffers certain drawbacks. Most notably, when many of the known position sensors are used in a relatively high temperature environment (e.g., 950° F. or more), the accuracy of the position sensor may deteriorate.
One example of a system in which a position sensor may be exposed to relatively high temperatures is an aircraft gas turbine engine. Gas turbine engines include various components, such as valves, that may be exposed to such high temperatures. Proper engine operation may, in many instances, rely on knowing the position of these components. However, if the accuracy of the position sensor suffers at high temperatures, the engine may not operate properly and/or most efficiently. Various systems and methods have been developed to compensate sensor inaccuracies for temperature. However, these systems and methods can be complex and relatively costly to implement.
Hence, there is a need for a position sensing system that can accurately determine, and provide a signal representative of, the position of one or more components in a relatively high temperature environment, that is relatively easy and less costly to implement. The present invention addresses one or more of these needs.